1. Technical Field
The present invention relates to apparatuses for developing latent fingerprints and the method of use thereof, and in particular, to the use of a chamber in combination with a heat source and a sublimation system containing a cyanoacrylate wherein the application of heat transforms the cyanoacrylate to vapor which is used in the quick and efficient development of latent fingerprints on objects contained in the chamber.
2. Related Art
The use of cyanoacrylate in the development of latent fingerprints on objects is well known and has been used as such for many years. Specifically, it is the reaction of the cyanoacrylate monomer and a catalyst that creates a microcrystalline vapor which adheres to fingerprints. Once the vapor cures, the cyanoacrylate forms a white polymer substance that reveals the fingerprint.
U.S. Pat. No. 4,556,579 to Lowell discloses a kit for developing latent fingerprints wherein liquid cyanoacrylate monomer is deposited onto a porous fiber plug made of cellulose acetate fibers. The resulting fumes from the chemical reaction generate any latent fingerprints that come into contact with the fumes. The kit also has a solvent for removing such fingerprints when desired.
Similar to the '579 patent, U.S. Pat. No. 4,613,515 to Reggio also discloses a kit for developing latent fingerprints on a solid surface. The kit contains an absorbent pad impregnated with a cyanoacrylic polymerization catalyst and one or more initiators, a promoter and an accelerator. The kit also provides a separate source of a polymerizable alpha-cyanoacrylate monomer with at least one inhibitor agent. In operation, a cyanoacrylate monomer is added to the surface of the pad and the pad is placed adjacent a surface believed to contain a fingerprint. The pad remains undisturbed until it generates a microcrystalline vapor from the reaction of the cyanoacrylic catalyst and monomer. The vapor travels through the air to the solid surface wherein upon contact with the surface it adheres to the latent fingerprint, thereby making the latent fingerprint visible.
There are several disadvantages with the kits of the '579 and '515 patents. The user must physically add the cyanoacrylate monomer to a pad or plug which may result in unwanted spillage or a wrong amount of cyanoacrylate monomer applied to the pad. The kits also consist of multiple components which increases the complexity of using the kits as well as increases the amount of waste.
U.S. Pat. No. 5,342,645 to Eisele, et al. discloses a metal cartridge containing a porous or fibrous pad such as steel or glass wool, impregnated with a cyanoacrylate ester and a volatile, emissive lanthanide metal-complex or actinide metal-complex. Upon the application of heat, e.g., a butane-powered torch, the chemical reaction produces a chemical vapor that is used to develop latent fingerprints. The principal disadvantages with the '645 patent is that it requires a heat resistent housing and the use of a butane torch, both requirements making the cartridge clumsy and potentially dangerous to use.
U.S. Pat. Nos. 5,348,759 and 5,424,092 to Weaver, et al. disclose a device for developing latent fingerprints. The device has a housing that contains a cyanoacrylate (either in liquid or solid form) and is adapted to receive a propane torch. Upon lighting the torch, the cyanoacrylate is vaporized and propelled toward the object to be tested on which any latent fingerprints appear within minutes. The user may replace the cyanoacrylate as needed for new tests. The disadvantage with these devices is that they require the use of a propane torch which increases the potential danger of using the devices. The devices also have multiple components including the need for additional cyanoacrylate to refill the housing, which increases the maintenance of the devices.
U.S. Pat. No. 5,395,455 to Bohanan discloses a method and apparatus for developing latent fingerprints on a portion of skin. The apparatus uses a heater to create a cyanoacrylate vapor which is propelled by a fan through a hose and comes in contact with skin. As seen in previous devices, this apparatus is very cumbersome to carry and use in field operation, and requires the use of a separate heater and fan which increases the maintenance effort.
U.S. Pat. No. 6,423,946 to Berka, et al. discloses an apparatus for developing latent fingerprints having a sealable container for depositing objects being tested for fingerprints. The container has an electrical heater as well as an exhaust means for evacuating air from the internal chamber. In operation, the method includes heating the container, placing objects within the chamber, adding a few drops of cyanoacrylate on an upper surface of an internal receptacle, covering the container, and pumping air from the container. After the fumes have developed any latent fingerprints on the objects within the chamber, the cover is removed and the objects are taken out. The disadvantage with the '946 device is that it is cumbersome to carry and use in the field. The user requires an electrical outlet for powering the heater. Also, the internal size of the chamber limits the number, size, and shape of the objects that can be placed in the container for testing.
Therefore, upon review of the prior art, there is a need for a simple, self-contained, re-chargeable apparatus for developing latent fingerprints. There is a further need for such an apparatus having a containment system for directing the fumes or vapors toward and around the object being examined.